In clinical trials in Japan, droxidopa has been shown to be effective in affecting blood pressure changes upon orthostatic challenge in patients with autonomic dysfunction, as well as reducing the severity and frequency of symptoms of orthostatic hypotension in these patients. The efficacy of droxidopa in ameliorating symptoms in patients undergoing dialysis has also been demonstrated in the literature and clinical trials conducted in Japan. The current study will investigate the clinical efficacy of two different doses of droxidopa in patients with intradialytic hypotension over a 4 week treatment period with a placebo control. The clinical efficacy will be evaluated by changes in hypotension- related symptoms, as well as changes in blood pressure prior to, during and following, HD sessions as compared to their pre-treatment baseline values.

This is a phase II, multi-center, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of droxidopa in HD patients with intradialytic hypotension. The study will be conducted in up to 15 centers, with a sufficient number of patients enrolled to allow 75 patients to be randomized into 3 study groups (25 randomized to placebo, 25 randomized to 400 mg droxidopa, and 25 randomized to 600 mg droxidopa). The study will consist of an initial screening period (up to 7 days) to confirm eligibility followed by a 2 week baseline, and a 4 week treatment period. During baseline and treatment visits SBP and DBP measurements will be collected using a consistent method immediately pre-, during and immediately post-dialysis. SBP, DBP and heart rate measurements will be taken every 20 minutes during HD sessions. There will be 19 scheduled visits, not including the post-treatment follow-up visit, during this trial; Visit 1 (Screening), Visits 2 through 7 (baseline and randomization), Visits 8 through 19 (tri-weekly treatment visits). Each visit will coincide with the patient's normal dialysis treatments. All patients will be followed for 30 days following the completion of the active treatment period (or premature withdrawal) to check for the occurrence of adverse events (AEs). Patients will attend the study center as out-patients. Eligible patients will be assigned a unique identification number at screening, and prior to the first treatment visit will be randomized to one of the following treatment groups: Group A: Droxidopa at 400 mg (2 capsules each containing 200 mg droxidopa plus one capsule with mannitol substituted for droxidopa) Group B: Droxidopa at 600 mg (3 capsules each containing 200 mg droxidopa) Group C: Placebo (3 capsules with mannitol substituted for droxidopa) Each patient will take 3 capsules 1 hour prior to each dialysis procedure with approximately 100 mL (typically half a glass) of water. The primary measure of efficacy will be the change from baseline (visits 2-7) in average mean arterial blood pressure compared to that during treatment (visit 14-19). The secondary measures of efficacy will be: * Change between baseline (visits 2-7) and treatment (visits 14-19) in average mean nadir systolic and diastolic blood pressures during hemodialysis; * Change in the number of hypotension-induced interventions during hemodialysis (HD) sessions; * Change in hypotension-induced symptoms measured during hemodialysis; * Change in daily symptoms associated with hemodialysis; * Change in fatigue using the Multidimensional Fatigue Inventory (MFI-20). The safety of droxidopa will be evaluated based on the occurrence of treatment-emergent adverse events (AE) and specific evaluation of blood pressure, heart rate (HR), ECG, and laboratory findings across the study.